Oxygenated and deoxygenated blood is allowed to mix as blood can move directly from one side of the heart to another through hole in the septum.
The blood leaving the heart from the atria carries less oxygen. As a result,
muscles receive less oxygen and therefore less energy.
All unborn babies have this hole. They do not need a double circulatory
system as their lungs do not function before they are born.
When born, this hole closes. If this does
not occur, the baby is born blue.
Damaged or weak valves
Blood could flow backwards and with less
pressure which means reduced pressure,
leading to poor circulation.
Artificial valves can be used as a
replacement.
Blocked coronary artery
If blocked, less blood flows to the
heart and it can lead to a heart
attack.
By-pass surgery uses veins transplanted from other parts of the body.
These take blood from the aorta, avoiding the blocked artery.
Heart assist devices
Reduced work done by heart muscles.
Often used for those people awaiting a heart transplant.
Advantages: Improves quality of life, keeps patients alive, no problems with waiting
for a donor or tissue match, no need for open heart surgery, no risk or rejection.
Disadvantages: Valves and pacemakers might need replacing.
Artificial Pacemakers
These are implanted under the skin and are a
substitute for a natural pacemaker.
BLOOD GROUPS, CLOTTING &
DONATION
Haemoglobin = The chemical you find
in red blood cells, carries the oxygen.
Platelets = Fragments of cells that are involved in blood
clotting.
White Blood Cells = They are involved with defending your
body against disease
Red Blood Cells = Contain haemoglobin,
carry oxygen around the body.
Plasma = 80% water,
liquid part of the
blood.
Blood Donor = Somebody who
donates their blood.
Blood Transfusion = When you receive
blood - The process in which the blood
donor's blood is put into your body.
CLOTTING
Prevents entry by
pathogens and stops
you losing too much
blood.
HAEMOPHILIA
An inherited disease in which blood fails to clot.
Queen Victoria
suffered from
Haemophilia.
PREVENTING BLOOD CLOTS
Anti-coagulant drugs e.g. warfin, heparin
and asprin, can help to thin the blood and
prevent clotting in vessels.
BLOOD CLOTTING = CASCADE PROCESS
Cut on the skin
Platelets exposed to air.
Several chemical reactions.
Meshwork of fibrin forms.
Clot forms
DONATING BLOOD
The blood donated by the donor must be compatible with the
recipient for ma successful transfusion.
If it not compatible then agglutination (blood
clumping) is caused. This is dangerous for the
patient.
BLOOD GROUPS
Your blood group depends on the presence or
absence of aggluinins.
2 proteins n the surface of RBCs (antigen A or B)
2 anti-bodies in blood plasma (serum) (anti-A or anti-B)
Donation of blood is based on the antigens on the surface of your RBCs.
Receipt of blood is based on the antibodies in
your plasma.
RESPIRATORY SYSTEM
Inspiration = Forcing air into the lungs.
Expiration = Forcing air out of the lungs.
Breathing = The exchange of gases between the lungs and surrounding air.
Respiration = The breakdown of glucose to release energy.
BREATHING
Breathing In
The intercostal muscles contract to lift the ribs up and outwards.
The diaphragm contracts ad moves down.
The volume inside the chest increases. Pressure is lower
inside the thorax than out.
This causes air to rush into your lungs and they inflate.
Breathing out
The intercostal muscles relax to lower tbs down and inwards.
The diaphragm relaxes and move up.
The volume inside the chest decreases.
Pressure is higher inside the thorax than out.
This causes air to rush out of the lungs and they deflate.
ALVEOLI ADAPTATIOMS
Good blood supply - maintains concentration gradient
Large surface area - provided my many small alveoli.